Vasostatins, N‐terminal products of chromogranin A, are released from the stimulated calf spleen in vitro

Abstract

Vasostatins are the N-terminal chromogranin A peptides 7 approximately 22 kDa. They have been shown to be present in several endocrine tissues and exhibit vasoinhibitory activity in vitro. In a first series of experiments, we investigated the presence and subcellular localization of vasostatins in the bovine splenic nerve. Experimental results, obtained using gradient centrifugation, showed that noradrenaline was enriched 25-fold in the large dense core vesicle fraction, compared with the original homogenate. In the latter fraction, the 7 and 18 kDa peptides were observed following immunodetection with antiserum to chromogranin A1-40 and laser densitometric scanning revealed these two fragments as the major N-terminal fragments. Subsequently, we examined the release of the 7 and 18 kDa peptides from perfused calf spleen during veratridine (20 microM) or 1,1-dimethyl-4-phenylpiperazinium iodide (20 microM) stimulation. In the prestimulation samples, we were not able to detect these peptides, however, following stimulation, the 7 and 18 kDa chromogranin A fragments became apparent. The vasostatin-immunoreactivity, in both bovine chromaffin granule lysate and calf spleen perfusate, elutes at the same retention time on reversed-phase high performance liquid chromatography. The present study demonstrated that vasostatins are present in the large dense core vesicles of sympathetic axons and are released from the nerve terminals in response to stimulation. The release of vasostatins from sympathetic nerves in the spleen suggest an in vivo function for N-terminal chromogranin A products of neuronal origin.

Antibacterial and Antifungal Activities of Vasostatin-1, the N-terminal Fragment of Chromogranin A

“…A study on the characterization of CGA-derived fragments, generated by the isolated retrogradely perfused bovine adrenal gland under basal conditions and during stimulation with acetylcholine, indicates that vasostatins are secreted from bovine adrenal medulla (58). In addition, vasostatins have been immunodetected in the large dense core vesicles traveling down sympathetic axons and are released from the nerve terminal in response to stimulation (59). The vasoinhibitory effect of vasostatins, which does not involve interference with endothelin-1 (a potent vasoconstrictor peptide) binding to its vascular receptor (60), has recently been associated with recombinant and synthetic human vasostatinderived fragments (61).…”

“…Absorbance was monitored at 214 nm, and elution was performed with a linear gradient as indicated on the right-hand scale. Arrow indicates the fraction corresponding to the antifungal peptide CGA [47][48][49][50][51][52][53][54][55][56][57][58][59][60] .…”

“…2), we decided to examine the role of the tripeptide Arg 43 -Gly 44 -Asp 45 and the length of the peptidic chain, testing the activities of the synthetic peptides CGA [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] , CGA , and CGA , respectively (Table III). The comparison of their activity with the activity of CGA [47][48][49][50][51][52][53][54][55][56][57][58][59][60] highlights several important points as follows: (i) CGA 41 ments CGA [47][48][49][50][51][52][53][54][55][56]…”

“…Then, the antifungal properties of the peptides included in the different peaks were tested. An active peptide corresponding to CGA [47][48][49][50][51][52][53][54][55][56][57][58][59][60] with an experimental molecular mass of 1732.9 Da ( Fig. 3B; expected molecular mass, 1733.1 Da) is active against N. crassa showing a minimal inhibitory concentration giving 100% inhibition of 7 M. Incubation of fungi with synthetic peptide corresponding to CGA [47][48][49][50][51][52][53][54][55][56][57][58][59][60] at increasing concentrations from 3 to 10 M (Table III) induces a decrease of fungal proliferation and the inhibition in the growth of filaments.…”

Structure-Activity Relationships of Chromogranin A in Cell Adhesion

“…Fragments corresponding to amino acids 1-76 and 1-113, named vasostatin-1 and vasostatin-2, inhibit vascular tension (18 -20). These N-terminal fragments are released from the adrenal medulla (20) and from sympathetic nerve terminals in response to stimulation (21). Vasostatin-1 can also inhibit parathyroid hormone secretion (22), is neurotoxic in neuronal/ microglial cell cultures (23), and can induce cell adhesion (24,25).…”